


Mirror

by LazySintastic13 (EmeraldWriter)



Category: Undertale (Video Game)
Genre: Alternate Universe - Underfell, Bara Sans, Breeding, Come Inflation, M/M, Mirror Sex, Multiple Orgasms, Overstimulation, Praise Kink, Pregnancy, Size Difference, Underfell Sans, kustard - Freeform
Language: English
Status: Completed
Published: 2018-07-09
Updated: 2018-07-09
Packaged: 2019-06-07 16:21:07
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 808
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15223007
Author URL: https://archiveofourown.org/users/EmeraldWriter/pseuds/LazySintastic13
Summary: Prompt given by Silverryu25 :D





	Mirror

**Author's Note:**

  * For [silverryu25](https://archiveofourown.org/users/silverryu25/gifts).



> Prompt given by Silverryu25 :D

He shouldn't have humoured him. He shouldn't have taken that hand and swooned at that confident smirk.  
  
Red covered his face with his arms, eyes tightly shut as he gritted his teeth to prevent the noise from coming out.  
  
He ignored the noisy squelching, of large strong hands tightly gripping his legs, spreading him wide open, as he was bounced on Sans' cock.  
  
"Come on, babe. You gotta see how gorgeous you look right now. Taking _all of me_ in."  
  
Red whimpered when Sans licked his nape, that large hot tongue lathering the full expanse of his cervical bones. His body couldn't help arching back to the other's wide chest, his head only reaching to the top of Sans' sternum when he fully sat on the other's cock. He was much smaller than the other skeleton in comparison, which made it even more embarrassing to _feel_ his stomach bulging upon every thrust.  
  
Red could feel every throb and twitch, and the relentless rubbing against his weak spots. He had already climaxed several times, squirting and had no doubt made a puddle on the floor as they were on the edge of the bed.  
  
"Look at you baby. So pretty. So beautiful." Sans groaned at the sight reflecting back, of Red's translucent ecto-stomach having tinges of blues and purples beneath the red.  
  
Red had long since lost the voice and energy to scream as the hot tears continued to stream down his face from the overstimulation and embarrassing feeling he felt being so open and praised. "Sa-nggghh." His toes curled, feeling another coiling tension ready to push him off the precipice.  
  
"Your arms, baby. Put down your arms. Please, Red. I need you to see. I need you to know just how fucking wonderful you are." Sans' constant begging and insistence had finally made Red succumb and relent to the other's wishes.  
  
Blurrily, he opened his eyes, blinking the tears away to clear his vision. What he saw looking back at him caused him to flush, involuntarily tightening against Sans. "N-n-nnogghh. _Aaah!"_  
  
"Yes, that's it. Do you see how pretty you are. So good to me, baby. So sweet and amazing."  
  
He could see it. He could see all of it.  
  
His pussy pushed and spread so wide to take in that large cock. His bones covered with perspiration. Of Sans' large hands gripping his femurs. His chest heaving with his soul glowing brightly beneath it. The drool dripping down his jaw. And his eye lights had turned heart-shaped.  
  
Obscene. He was so debauched. A downright mess.  
  
And Sans loved it. He loved every single part of him. The hungry look and appreciation never abating from his gaze, and Red felt even hotter from the blunt want just oozing from Sans.  
  
Red keened, his arms flung back over his head, clutching against the other's sternum as another orgasm shook his core. His juices spilling in a gush, dripping on the thrusting length.  
  
The sudden tightening caused Sans to howl and bare his fangs, as he hilted himself and spurted copious amounts of his cum into the spasming channel. Due to his size, it acted more of a plug.  
  
Red's stomach distended as if he were pregnant.  
  
And the imagery had Sans grin with satisfaction, while Red let out a breathless and tired laugh; both slowly coming down from their high.   
  
Red's voice was hoarse and weak when he spoke. "G-Geez, Sans. I m-might really g-get pregnant t-this time."  
  
_"Good."_  
  
The short skeleton flushed even more, his body shuddering at the deepened voice and the underlying possessiveness in it.  
  
And looking at himself again in the mirror, with his back against Sans, his own hands on his large stomach, somehow, he didn't particularly mind if it actually happened.

* * *

Bone-us: 

Sans breathed out a sigh as the familiar jangle of keys resounded in his ears. The click before having the door give way, made him feel as if he had truly finished a long day of work. 

"Welcome back Sans!" 

The aforementioned skeleton looked down at his husband, wearing a loose yellow gown to cover his large belly. A warm smile couldn't help but make its way to his face, leaning down to kiss Red on the mouth. "Thanks, sweetie. Good to be back. How's the back?" 

"Much better than before. Wished the little runts wouldn't move so much." Red chuckled as he patted his stomach. 

"Heh, you're still so gorgeous babe. I'm so lucky." Red had to roll his eyes, even if he couldn't hide the blush on his cheeks. "You say that every time Sans." 

Sans lifted Red carefully, making him sit on his arm whilst the latter casually held onto him; very much used to being carried around by his big spouse. "And I'll keep saying it." 

"Pfft. Yeah? Even when I become a whale?" 

"Even then Sweetheart."


End file.
